Say that we are interested in the criminal justice effects caused by Miranda v. Arizona. Since the ruling obliges police officers to inform criminal suspects in custody of their right to consult with an attorney and against self-incrimination, a possible implication of the ruling may be that suspects are less likely to divulge incriminating information having heard their rights following their arrest. This may make it harder for prosecutors to make their case—which, in turn, may lead to lower conviction rates. Given our theory, the components of our empirical study might be as follows:

Hypothesis: “Homicide conviction rates in Massachusetts will be lower in the post Mirandav Arizona period.”

An important point to make here is that if we are interested in inferring the general effects of Miranda on criminal justice procedures, a failure to reject this single test on homicide conviction rates in Massachusetts may not be enough to categorically declare that Miranda has hindered the work of prosecutors. There may be something unique about homicide convictions and/or Massachusetts which may obscure the general effect of the ruling. For this reason, we would want to expand the observable implications of our theory—perhaps testing conviction rates for many types of crimes in all states. For examples of such studies, see Cassell and Fowles (1997), Donohue (1998), and Leo (2000) for a review of empirical studies on the consequences of Miranda.